Big Gemini (or "Big G") was proposed to NASA by McDonnell Douglas in August, 1969, as an advanced version of the Gemini spacecraft system. It was intended to provide large-capacity, all-purpose access to space, including missions that ultimately used Apollo or the Space Shuttle.

The study was performed to generate a preliminary definition of a logistic spacecraft derived from Gemini that would be used to resupply an orbiting space station. Land-landing at a preselected site and refurbishment and reuse were design requirements. Two baseline spacecraft were defined: a nine-man minimum modification version of the Gemini B called Min-Mod Big G and a 12-man advanced concept, having the same exterior geometry but with new, state-of-the-art subsystems, called Advanced Big G. Three launch vehicles-Saturn IB, Titan IIIM, and S-IC/S- IVB-were investigated for use with the spacecraft. The Saturn IB was discarded late in the study.

The spacecraft consisted of a crew module designed by extending the Gemini B exterior cone to a 419-cm-diameter heat shield and a cargo propulsion module. Recovery of the crew module would be effected by means of a gliding parachute (parawing). The parametric analyses and point design of the parawing were accomplished by Northrop- Ventura Company under a subcontract, and the contents of their final report were incorporated into the document. The landing attenuation of the spacecraft would be accomplished by a skid landing gear extended from the bottom of the crew module, allowing the crew to land in an upright position. The propulsion functions of transfer, rendezvous , attitude control, and retrograde would be performed by a single liquid propellant system, and launch escape would be provided by a large Apollo-type launch escape system.

In addition to the design analyses, operational support analyses and a program development plan were prepared.

Specifications

• Crew Size: 9 to 12
• Length: 11.5 m.
• Maximum Diameter: 4.27 m.
• Habitable Volume: 18.7 m³
• Mass: 15,590 kg
• Payload: 2,500 kg
• Launch Vehicles: Titan 3M, Saturn IB, Saturn S-IC/S-IVB.

See also

• Project Gemini
• Manned Orbiting Laboratory
• Titan (rocket family)

External links

• Big Gemini - Encyclopedia Astronautica
• NASA History Series Publications